When greenhouse gas mitigation commitments are made, the standard form is to ‘reduce by a certain percentage below the level in a base year by a target year.’ For example, 5% below 1990 levels by 2012. This can be easily converted into a target in absolute emissions. Say, cutting from 1,000 megatonnes (MT) in 1990 to 950 MT in 2020.
I have criticized the process of target-setting before, arguing that the ability of organization to set targets that look ambitious can obscure the absence of plans to actually achieve those reductions. In the end, it makes sense to focus our efforts on cutting emissions, rather than haggle over whether to cut by 65% or 70% by 2050.
Given that targets won’t be vanishing any time soon, I do have a proposal for improving one aspect of them. Rather than expressing targets are just an absolute level of emissions at a set date, they should be expressed as both an absolute level and a rate of reduction to be achieved by a target date. A financial equivalent would be to say: by 2010, I will have paid off 50% of my mortgage, and will be paying more off at a rate of $10,000 per year. What this avoids is the theoretical situation in which a state or other entity limps across the finish line, meeting a 2020 target with no new ideas and initiatives for reaching their 2050 target. This would be akin to a pharmaceutical company that has all its blockbuster drugs go off-patent simultaneously, at the same time as it has no promising new ones in the pipeline (not a hypothetical scenario for a significant number of drug companies right now).
Having a double rather than a single target doesn’t affect the disjoint between commitments and achievements, but it may help foster the kind of mindset required to build a low-carbon society.
Projections for five or ten years out tend to be very approximate, anyhow.
Why would adding a second element to them be useful?